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A Decay of polarized particle into two spinless

  1. Apr 16, 2016 #1
    Hi All, I want to understand the decay of a spin-1 massive vector particle into two spinless massive particles.

    Given a massive vector particle V with spin Sz = +1, 0, -1 decays into 2 massive spinless particles. I have to compute the amplitude M but I dont know what should I do with the polarization vectors?

    Hence my Qs. is that, does the Sz vectors becomes the polarization vectors?
    is the angular momentum and/or Sz conserve?

    I am kind of al-confuso because never did any polarized photon-less decay before.
    any help is much appreciated.
  2. jcsd
  3. Apr 17, 2016 #2


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    Do you have a concrete model at hand? The calculation can be done in the usual way using Feynman rules. Usually you are interested in the unpolarized cross section, i.e., you average ##|\mathcal{M}_{fi}|^2## over the polarization states of the decaying vector particles in the initial state.
  4. Apr 17, 2016 #3
    Thanks for the reply,
    so e.g for Sz=1 what polarization vector should I use assuming the axis is z.?
  5. Apr 17, 2016 #4
    Okay the original Qs. with V=vector particle and S1 & S2 are spinless is that;

    Let V--->S1S2 in the rest frame with S1 emitted in the x-z plane at and angle theta respect to z-axis.
    show that the decay rates for polarization states of V with spin Sz=+1,-1,0 along the z-direction
    are proportional to sin^2(theta) and cos^2(theta) respectively.
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